A. Field of the Invention
This invention relates to a method and an object according to the species of the independent claims. The invention relates in particular to a method for manufacturing a contactlessly readable identification document with integrated IC, which can be used as an identity card or as a data page in a passport booklet, as well as to a corresponding identification document.
B. Related Art
Identification documents such as identity cards or passports are increasingly provided with transponder arrangements which consist of a chip module, which contains an IC, and an antenna connected therewith. These chip-coil arrangements allow the data stored in the IC to be contactlessly read. The manufacturing of such identification documents is typically effected by laminating at least one core layer and two cover layers, the chip-coil arrangement being integrated into the core layer. A problem with respect to the durability of such identification documents is the bond between the IC-module and the document body. The two consist of different materials, the module material is hard and high-melting, while the material employed for the document body is comparatively soft and readily laminatable. The different material consistence of IC-module and document body, upon long-term use of a corresponding identification document, sometimes leads to the formation of cracks—emanating from the border region between chip module and document body—in the bordering layers. The cracks spread into the cover layer lying next and impair appearance and mechanical stability of the identification document.
In order to prevent such cracks in portable data carriers used as identification documents, it has been proposed in WO 2007/089140 A1 to provide a further layer between module upper side and cover layer, and to provide a non-continuous auxiliary layer insert between the further layer and the cover layer, which is slightly larger than the module upper side and consists of a rubberlike material with a particularly high coefficient of expansion. The auxiliary layer insert makes sure that cracks possibly emanating from the transition region between module and core layer do not spread into the cover layer in any case. An analogous auxiliary layer insert can also be provided for the narrower underside of the module.
From WO 2009/135823 A1 there can be inferred, likewise for the purpose of eliminating the development of cracks, a structure for a multilayer body of an identification document, in which individual layers contain inserts made of a softer material. A chip module to be integrated into the document body is now arranged exactly in such a patch made of softer material. The extension of the patch here is larger than the module. Upon laminating, the softer material then flows completely around the module and embeds it form-fittingly. In this way, stress zones leading to cracks can be prevented. Realizing the patchwork-like layers is elaborate, however.
From DE 199 21 230 A1 there is known a method for manufacturing a chip card with direct use of a thinned chip instead of an otherwise usual chip module. The chip is manufactured in a wafer and placed at the component side with interposition of a detachable interim adhesive on a carrier band where it is thinned from the back. After removal of the interim adhesive, the thinned chip is inserted in a cavity prepared in a chip card body. In so doing, it is fixed in the cavity with the aid of a further adhesive applied for this purpose on the back of the chip. Onto the component side there is then laminated a chip card foil, on which there are formed conductor paths which contact the component side of the thinned chip. The problem of a possible cracking does not exist with especially thinned chips, because in the finished card body they occupy with their minimum thickness and their small area only a very small installation space, from which there do not emanate any crack-forming disruptions. The handling of the chips, however, is very elaborate in comparison to the handling of chip modules.
In the book, “Vom Plastik zur Chipkarte” by Y. Haghiri, T. Tarantino, Carl Hanser Verlag, Munich, 1999, there are described manufacturing methods for chip cards, in particular the lamination technique.
It is the object of the invention to state a method which allows crack-resistant data carriers to be manufactured without substantial interventions in the lamination process.